Electronic apparatus with a solar battery

ABSTRACT

In the case of using a solar battery formed by growing an amorphous silicon film on a substrate as a watch face for an electronic watch, there had been great restrictions with regard to the design of the watch face. If it is possible to impart transparency to light to the substrate onto which is formed a solar battery, so that it is possible to achieve a form of solar battery that is not perceivable, it is possible, by using a substrate onto which is formed this solar battery either on the watch face or on a protective glass crystal or the like, to achieve a watch with a solar battery not restricted with respect to watch face design.

FIELD OF THE INVENTION

[0001] The present invention relates to an electronic apparatus, andmore specifically to an electronic apparatus with a combination of asolar battery and an information display means.

BACKGROUND ART

[0002] In the case in which a solar battery is used as a primary cell ofan information display that includes an electronic watch, a solarbattery module is often positioned at the watch face, in order toreceive light for conversion to electrical energy.

[0003] That is, as shown in FIG. 3, a solar battery module 3, made up ofa solar battery formed on a substrate, is disposed at the position of awatch face 4, this being used as the watch face as is. Light isconverted to electrical energy and used to charge a secondary cell suchas a nickel-cadmium battery, electrical energy from the secondary cellbeing extracted so as to drive the watch.

[0004] Another means, as shown in FIG. 4, is one in which a solarbattery module 3 is disposed below the watch face 4. In either case, ina solar battery module that obtains an electromotive force obtained fromfour solar battery elements, the shape shown in FIG. 9 is usually used.

[0005] In the configuration of a solar battery shown in FIG. 9, as shownin FIG. 10, the electrodes 5 of the four solar batteries 6 are connectedby using an extended electrode from part of the electrodes,electromotive force being extracted from output electrode 7 and 7′provided at these ends.

[0006] In a solar battery 6 of the past, as shown in FIG. 19(A), solarbattery 6 is formed by laminating, onto a transparent substrate 11,electrodes 12 and 14 and, for example, a P-I-N type amorphous siliconlayer 13, wherein, because the electromotive force occurring duringoperation is limited to 0.5 V or so, for use as a power supply in anelectronic watch, it is not possible with one element 6 to charge asecondary cell such as a nickel-cadmium battery.

[0007] Given the above, the structure adopted is one in which aplurality of solar batteries 6 are disposed on the substrate 11, theseelements 6 being connected in series so that the electromotive forcesthereof are added, thereby generating a voltage that charges a secondarybattery.

[0008]FIG. 19(B) is a schematic representation of the connectionstructure of the solar battery 6. This solar battery 6 is formed byforming a transparent conductive film 12 onto a glass substrate 11, ontowhich is then formed a P-I-N type amorphous silicon film (hereinafterabbreviated a-Si film), and further onto which is formed a metalelectrode film 14.

[0009] An electromotive force generated because of the light incidentfrom below the substrate 11 can be extracted from the transparentconductive film 12 and the metal electrode film 14 that surround thea-Si film 13 on both sides.

[0010] The laminate structure on the top of the substrate 11 is dividedbetween left and right at substantially the center in FIG. 19(B), andboth sides thereof are other solar battery element regions, the left andright sides being called element A and element B, respectively, for thepurpose of the description herein.

[0011] The metal electrode film 14 of the element A and the transparentelectrode film 12 of the element B are linked, thereby connecting thesolar battery elements 6 and 6′ in series.

[0012] At locations other than FIG. 19(B) as well, there is the sametype of connection between the metal electrode film 14 and thetransparent conductive film 12 of adjacent elements 6 and 6′, therebymaking a series connection between a plurality of solar battery elements6 and 6′ formed on the substrate 11, so as to form a solar battery withthe desired electromotive force.

[0013] A method for manufacturing a solar battery such as noted above isdescribed below, with reference to FIG. 19(A) and FIG. 19(B).

[0014] First, as shown in FIG. 19(A), a transparent conductive film 12is formed on the substrate 11. This is, for example, an SnO2 film formedby a CVD process.

[0015] Then, laser machining is done of the SnO2 film so as to patternit to the desired electrode shape. Next, a CVD process is used tolaminate an a-Si film 13 onto the transparent conductive film 12, thisbeing then laser machined to pattern the desired shape.

[0016] Additionally, a metal film that will serve as the metal electrodefilm 14 is sputtered onto the transparent conductive film 12 and thea-Si film 13, and the metal electrode film 14 is again laser machined toobtain the desired patterning shape for an electrode.

[0017] A solar cell such as shown in FIG. 9 or FIG. 10 having aconnection cross-sectional structure as shown in FIG. 19(B) is completedin this manner. The cross-sectional construction other than theconnection part is as shown in FIG. 19(A).

[0018] The relationship between the information display means of thepast and a solar battery module including a solar battery 6 is one inwhich, with an opaque solar battery 6 of a special color, for example,it is difficult to use this at the surface of an information displaymeans of an electronic apparatus including a watch face orliquid-crystal display of an electronic watch.

[0019] For example, the general approach is to form this integrally withthe watch face, or to dispose it on the lower side of the watch faceand, for that purpose, for example, in the case of a watch face, holesare appropriately formed in the watch face, so that sunlight can strikethe solar battery 6, or the solar battery 6 itself is made a blackishcolor or other color that does not stand out, with the solar battery 6itself being visible to the outside.

[0020] Another past example is, as shown in FIG. 11, one in which asolar battery 6 is annularly disposed around the periphery of the watchface.

[0021] In a watch configured as noted above, however, the watch becomesspecial and more costly, and is either limited in application or limitedin the quantity that will be sold.

[0022] In the same manner, in an information display means other than awatch, such as an electronic apparatus in which a solar battery 6 drivesa display means that uses a liquid crystal, it is impossible to disposean opaque solar battery on the surface of the liquid-crystal displaymeans, and difficult to form holes in the liquid-crystal display for thepurpose of causing sunlight to pass therethrough.

[0023] Additionally, as a method to solve the above-noted technologicalproblems, there has been a proposal for a watch or a liquid-crystaldisplay in which a solar battery is formed linearly with a fine width ona transparent substrate, so that the solar battery is formed so as tocover the upper surface of a information display so as to be invisibleto the human eye.

[0024] In the prior art, however, there was merely a vague indication ofthis configuration, and neither a technical basis nor disclosed data toindicate just what dimension would produce a desirable effect, the priorart, therefore, not going beyond the realm of an idea.

[0025] In a watch with a solar battery of the past as described above,in the case in which a solar battery module is disposed as the watchface, the presence of the solar battery module imposes restrictions withregard to watch face design.

[0026] Even if the solar battery module is disposed below the watchface, the watch face must have transparency to light, thereby beingrestricted with regard to materials and design, meaning that it is notpossible to use a watch face with various materials and designed.

[0027] If it were possible to impart transparency to light to a solarbattery module 3 formed by a solar battery 6 on a substrate, and alsoform the solar battery 6 so that it not visible to the human eye, itwould be possible to use a solar battery module 3 formed by a solarbattery 6 on a substrate on an information display such as aliquid-crystal display or watch face, or in a protective glass crystal,thereby enabling the fabrication of an electronic apparatus, such as asolar battery watch, without restrictions imposed with regard to designof the watch face or liquid-crystal display.

[0028] Additionally, if the configuration is made so that efficientopto-electromotive force is obtained with a solar battery formed aslinear elements with even a finer width, it is possible not only toincrease the amount of electricity generated, but also to make the solarbattery smaller.

[0029] Accordingly, it is an object of the present invention to improveon the above-noted problems of the past, by providing an electronicapparatus with an information display means driven by a solar battery,wherein, a solar battery by a linear strip of fine width that cannot beseen by the human eye is formed on a transparent substrate and coversminimally a part of the surface of a prescribed information display.

DISCLOSURE OF THE INVENTION

[0030] In order to achieve the above-noted objects, the presentinvention has the following basic technical constitution. Specifically,an electronic apparatus with a solar battery according to the presentinvention is an electronic apparatus in which the major portion of aninformation display surface of an information display means is coveredby a transparent substrate having a solar battery, wherein the solarbattery is formed on the transparent substrate as a linear element offine width so that the major transparent part of the transparentsubstrate is not blocked thereby, the solar battery being formed so thatit protrudes minimally at one main surface of the transparent substrate,the transparent substrate having the solar battery being disposed on theside of the direction of light incidence with respect to the informationdisplay means, and the solar battery formed so as to protrude from thetransparent substrate being formed so as to oppose the informationdisplay means on the transparent substrate.

[0031] That is, in a electronic apparatus according to the presentinvention, there is particular use of a side wall formed in thelongitudinal direction of the solar battery to collect more incidentlight, thereby efficiently generating electricity, by making theconfiguration such that the solar battery protrudes from the uppersurface of the transparent substrate.

[0032] Another aspect of the present invention is a solar batterymodule, in which a solar battery is formed on a surface of a transparentsubstrate, the solar battery being formed as a linear element of finewidth, so that a major transparent part of the transparent substrate isnot blocked thereby, the solar battery being formed so that it protrudesminimally at one main surface of the transparent substrate.

[0033] Yet another aspect of the present invention is a watch with asolar battery, in which the above-noted solar battery module is disposedon the watch face.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0034]FIG. 1 is a cross-sectional view showing an example of theconfiguration of an electronic apparatus with a solar battery accordingto the present invention.

[0035]FIG. 2(A) is a cross-sectional view showing an example of theconfiguration of a watch with a solar battery according to the presentinvention, and FIG. 2(B) is a cross-sectional view showing anotherexample of the configuration of a watch with a solar battery accordingto the present invention.

[0036]FIG. 3 is a cross-sectional view showing an example of theconfiguration of a watch with a solar battery of the past.

[0037]FIG. 4 is a cross-sectional view showing another example of theconfiguration of a watch with a solar battery of the past.

[0038]FIG. 5 is a plan view showing an example of the configuration of asolar battery module according to the present invention.

[0039]FIG. 6 is a plan view showing another example of the configurationof a solar battery module according to the present invention.

[0040]FIG. 7 is a plan view a different example of the configuration ofa solar battery module according to the present invention.

[0041]FIG. 8 is a plan view showing yet another example of theconfiguration of a solar battery module according to the presentinvention.

[0042]FIG. 9 is a plan view showing an example of a solar battery moduleof the past.

[0043]FIG. 10 is a plan view showing another example of a solar batterymodule of the past.

[0044]FIG. 11 is a plan view showing a different example of a solarbattery module of the past.

[0045]FIG. 12 is a graph showing the relationship between the elementsize of the solar battery in the present invention and the electricalcharacteristics thereof.

[0046]FIG. 13 is a graph showing the relationship between the surfacearea occupied by the solar battery in the present invention and thelight transmissivity.

[0047]FIG. 14(A) through FIG. 14(C) are drawings illustrating the amethod for manufacturing a solar battery module of the presentinvention.

[0048]FIG. 15 is a drawing showing an example of a solar battery moduleobtained using the present invention.

[0049]FIG. 16(A) and FIG. 16(B) are drawings showing another example ofa solar battery module in the present invention.

[0050]FIG. 17(A) and FIG. 17(B) are drawings showing an example of adifferent solar battery module in the present invention.

[0051]FIG. 18(A) through FIG. 18(F) are drawings showing a method ofconfiguring the connection part of the electrodes in a solar batterymodule of past.

[0052]FIG. 19(A) and FIG. 19(B) are drawings which show an example of amethod for configuring the connection part of the electrodes in a solarbattery module of the past.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] A specific example of an electronic apparatus with a solarbattery according to the present invention is described below in detail,with reference made to the drawings.

[0054] Specifically, FIG. 1 through FIG. 3 are drawings showing anexample of the configuration of an electronic apparatus according to thepresent invention, FIG. 1 showing an electronic apparatus 10 in whichthe major portion of the surface of an information display 2 of aninformation display means 1 is covered by a solar battery module 3formed by a transparent substrate 4 having a solar battery 6, whereinthe solar battery 6 is formed on the transparent substrate 4 as a linearstrip of fine width, so as not to block a major transparent portion ofthe transparent substrate 4, the solar battery 6 being formed so as toprotrude minimally one main surface of the transparent substrate 4, asolar battery module 3 formed by the transparent substrate and includingthe solar battery 6 being disposed on the side of the direction onincidence of light from a light source such as sunlight, fluorescentlight, or other light energy with respect to the information displaymeans 1, and the solar battery 6 that is formed so as to protrude fromthe transparent substrate 4 being formed on a surface 5 opposing theinformation display means 1 on the transparent substrate 4.

[0055]FIG. 2(A) shows an electronic watch 10, in which the informationdisplay means 1 is a watch face, wherein the solar battery module 3 isdisposed over the watch face 1 provided under the hour and minute hands8 and 9 of within the protective glass 7 on at least part, andpreferably over the entire surface of the watch face 1.

[0056] In FIG. 2(A), although not clearly shown, it is preferable thatthere be some distance between the information display means 1 and thesolar battery module 3 that is formed by a transparent substrate 4 thatincludes a solar battery 6.

[0057]FIG. 2(B) shows a configuration in which a solar battery module 3such as shown in FIG. 3 is attached inside the protective glass so thatthe surface at which the solar battery 6 protrudes is opposite the watchface.

[0058] In FIG. 2(A) and FIG. 2(B), 21 denotes a support of the watchface 1, and 22 denotes a movement having a drive motor for the hour andminute hands.

[0059] In the electronic apparatus 10 with a solar battery according tothe present invention, as noted above, it is desirable that a majorportion of the information display surface of the information displaymeans 1 be covered by the transparent substrate 4 having a solar battery6, the solar battery 6 being formed on the transparent substrate 4 so asnot to block a major transparent portion of the transparent substrate 4.

[0060] Although not specified, it is desirable that the informationdisplay means 1 be one type selected from a group of, for example, aliquid-crystal display, a display panel comprising numerals andgraphics, and the face of a watch.

[0061] Therefore, a digital or analog watch is an example an electronicapparatus 10 of the present invention.

[0062] Each of the solar batteries 6 of the present invention isrequired to be formed so as to protrude from the transparent substrate 4and, as a result, the side wall 30 of the solar batteries 6 isconfigured to serve as a light-incidence section.

[0063] That is, the side wall 30 of a solar battery 6 in the presentinvention is configured so that part of the sunlight passing through thetransparent substrate 4, or reflected light from the information displaymeans 1 is incident thereto. By adopting this configuration, in additionto sunlight or light from another light source incident to, for example,an amorphous silicon layer that serves as electrical generating layer13, via the transparent substrate 4 and a transparent electrode film 12in contact with the transparent substrate 4, in the same manner lightenergy from the side wall 30 of the solar battery 6 is taken into theelectrical generating layer 13, thereby enabling the maximumopto-electromotive force in the solar battery 6.

[0064] The electrode 14 provided at the edge part of the protrusion inthe solar battery 6 of the present invention can be a metal electrode,and can also be a transparent electrode 14 such as the transparentelectrode 12.

[0065] It is desirable that the protruding height (H) of the solarbattery 6 from the transparent substrate 4 be such that, the total ofthe heights on both sides of the solar battery 6, (H1+H2), on both sidewalls formed in the longitudinal direction of the solar battery 6 is 1%or more, preferably being 1% to 30%, of the total of the length(H1+H2)+(L) summing up a length L of a portion of a cross-sectional areaprotruding from the transparent substrate and formed perpendicular tothe longitudinal direction of said solar battery and which beingsubstantially parallel to said transparent substrate, and a total of thetwo heights (H1+H2) corresponding to the side walls on both sidesthereof.

[0066] Additionally, in the present invention, the solar batteries 6, asshown in FIG. 5 through FIG. 8, are formed as linear elements 35 havinga width that is fine enough that they are not visible to the eye, theplurality of narrow linear elements 35 being disposed either mutuallyparallel or adjacent with a prescribed spacing therebetween.

[0067] The width L of the linear elements 35 and the placement spacing Pof each linear element 35 are desirably established to satisfy thecondition that the linear elements 35 in the solar battery module 3 thatincludes the solar batteries are not visible to the human eye.

[0068] The narrow linear elements 35 used in the present invention arepreferably linear or curved.

[0069] It is desirable that the transmissivity of the solar batterymodule 3 on which are formed a plurality of solar batteries 6 used inthe present invention be 70% or greater.

[0070] That is, it is desirable in the present invention that the widthL of the narrow linear elements which are the solar batteries be asnarrow as possible, and that the spacing between the narrow linearelements 35 be as wide as possible.

[0071] However, because making the narrow linear elements extremelynarrow increases their resistance, thereby hindering the electricalgenerating effect, it is desirable this width have a narrow-side limitof approximately 8 μm.

[0072]FIG. 12 is a graph showing the voltage-versus-current relationshipwhen the width of the narrow linear elements 35 making up the solarbattery in the present invention is varied (the case in which theelement size (um) is changed), these results obtained by a comparisonexperiment in which the height (H) of the narrow linear elements 35 washeld fixed at 0.5 μm.

[0073] As can be understood from FIG. 12, the smaller the size of theseelements is made, the better is the current efficiency per unit ofsurface area.

[0074] This is thought to be because of a large amount of light that isincident to the solar battery 6 from the side walls.

[0075] However, if the element size of the solar battery 6 becomessmaller than 6 μm, process damage causes noticeable deterioration in theelement characteristics, and it is thought that the limit value isapproximately 8 μm.

[0076] Considering the above-noted experimental results, it is desirablethat the width L of the narrow linear elements 35 making up the solarbatteries in the present invention be 200 μm or smaller, and furtherthat preferably L be 20 μm or smaller.

[0077]FIG. 13 is a graph showing the relationship between the portion ofthe transparent substrate 4 occupied by the solar batteries 6 and theoptical transmissivity, from which it can be understood that, even whenthe total surface area of the narrow linear elements 35 represents 20%of the total surface area of the transparent substrate 4, the lighttransmissivity is still above 70%.

[0078] It is undesirable that the total surface area of the narrowlinear elements 35 is greater than 20% of the total surface area of thetransparent substrate 4, it is not preferable because the lighttransmissivity of the transparent substrate 4 falls below 70%.

[0079] It is desirable in the present invention that the mutual spacingP between narrow linear elements 35 making up the solar batteries, be atleast 100 μm.

[0080] It is desirable that a group of narrow linear elements disposedin a solar battery module 3 be mutually connected in parallel, andstraight-line linear elements 35 can be disposed so as to be mutuallyparallel, while curved narrow linear elements 35 can be disposed so asto-be mutually parallel or mutually concentrically with a prescribedspacing therebetween.

[0081] For example, FIG. 5 shows an example of the disposition solarbatteries 6 formed by linear elements 35 formed in a solar batterymodule 3, in which a plurality of arc-shaped curved narrow linearelements are concentrically arranged, with bridges 36 making connectionsbetween individual curved narrow linear elements 35.

[0082] That is, the placement pattern of the narrow linear elements 35in FIG. 5 is that of a spider' web.

[0083]FIG. 6 shows another example of a solar battery module 3 in thepresent invention, wherein a group of narrow linear elements 35 formedon the transparent substrate 4 is formed by mutually different groupsthereof, there being four groups in the case of this example, the narrowlinear elements 35 that make up each of the groups being mutuallyparallel, with the base parts thereof being connected by an electrode37, an appropriate connection electrode 38 making a series connectionbetween these groups.

[0084]FIG. 7 shows another configuration of the solar battery module 3of the present invention, in which narrow linear elements 35 formed on atransparent substrate 4 such as in the example of FIG. 6 are dividedinto four groups, wherein a plurality of narrow linear elements 35 a,which are mutually parallel and form one group, are mutually interleavedwith a plurality of narrow linear elements 35 b, which are mutuallyparallel and form another group.

[0085]FIG. 8 shows a different configuration of the solar battery module3 of the present invention, in which a plurality of narrow linearelements 35 formed on a transparent substrate 4 such as in the exampleof FIG. 6 are divided into four groups, wherein a plurality of narrowlinear elements 35 c, which are mutually parallel and form one group,and a plurality of narrow linear elements 35 d, which are mutuallyparallel and form another group, are disposed so that the arrangementdirections thereof are mutually different, the difference in angle ofarrangement therebetween being 90 degrees in this example.

[0086] In the same manner, the arrangement directions of all adjacentgroups differ by 90 degrees.

[0087] The electrical generating layer 13 that is surrounded by the twoelectrodes 12 and 14 in the solar battery 6 of the present invention canbe single-crystal silicon, or can also be an amorphous silicon film, andcan also be made of any other material, as long as the material hasopto-electromotive force.

[0088] It is desirable that the surface of the information display meansin the electronic apparatus 10 of the present invention be configured sothat it can efficiently reflect incident sunlight.

[0089] Specifically, it is desirable that the configuration be such thatit is easy to reflect light at-the surface of either the liquid-crystaldisplay means or the watch face.

[0090] In the present invention, it is preferable that the solar batterymodule 3 be disposed below the protective glass crystal of the watch orthe like, that is, on the surface on the opposite side from the side ofsunlight incidence, this being the surface facing the informationdisplay means 1.

[0091] In the present invention, by adopting the above-describedconfiguration, the solar battery elements become invisible to the nakedeye, light passing through parts on which the solar battery elements arenot formed making it possible to verify a member on the rear surface ofthe solar battery module onto which is formed the solar batteries fromthe outside o the solar battery module. Therefore, when using this solarbattery on a protective glass crystal of a watch, it is possible tofabricate a solar battery watch without restriction placed on thedesign.

[0092] Furthermore, in the present invention, the electromotive force ofthe solar battery 6 itself can be increased over a solar battery of thepast and, by doing so, it is possible not only to lengthen the drivetime, but also to make the solar battery itself smaller.

[0093] A method of configuring a solar battery module 3 that includes asolar battery 6 and a transparent substrate 4 according to the presentinvention, as shown in FIG. 1, is described in detail below.

[0094] In the present invention, a transparent substrate made of glass,plastic, or the like is used as a substrate for forming the solarbatteries.

[0095] The method used to fabricate the solar battery is that of first,as shown in FIG. 14(A), growing a transparent conductive film 12 ontothe substrate 4, and then using a photolithography process (hereinaftersimply referred to as lithography) to form a resist pattern 40thereover.

[0096] The case in which indium tin oxide (ITO) is used as thetransparent conductive film 12 is described herebelow.

[0097] First, an ITO 12 film is formed by sputtering. The sputteringconditions when this is done are introduction of argon gas at 100 sccmand oxygen gas at 2 sccm into the sputtering apparatus chamber, apressure within chamber of 5 mTorr to 30 mTorr, and application of 1 kWto 3 kW of high-frequency power (13.56 MHz) to form a plasma.

[0098] Next, as shown in FIG. 14(B), the above-noted resist film 40 isused as a mask pattern to etch the transparent conductive film 12.

[0099] The etching of the ITO film 12 is done by dry etching using aprocessing agent that is a 3:5:2 mixture of ferric oxide, hydrochloricacid, and water.

[0100] After the above, as shown in FIG. 14(C), the resist is firstpeeled away, thereby forming an a-Si film 13 and the ITO film that isthe upper electrode film 14 onto the surface of the transparentsubstrate 4 and the transparent electrode 12. The upper electrode film14 can be a metal film made of titanium, aluminum, or the like, and itis desirable that this be a transparent conductive film in order to makeuse of reflected light from the watch face as well in generatingelectricity.

[0101] The a-Si film is grown using a plasma CVD process. When this isdone, to form a P-type a-Si film 13, silane gas at 500 sccm and diboranegas at 0.1 sccm to 1 sccm are introduced into the plasma CVD apparatuschamber, the pressure in the apparatus chamber being 0.5 Torr to 2 Torr,and 50 W to 300 W of high-frequency electrical power (13.56 MHz) beingapplied to generate a plasma so as to break down the gas, the substratebeing placed on an electrode at a temperature of 250° C.

[0102] To grow an I-type a-Si film 13, silane gas is introduced into theplasma CVD apparatus chamber at 500 sccm, the pressure within which is0.5 Torr to 2 Torr, and 50 W to 300 W of high-frequency electrical poweris applied (13.56 MHz) so as to generated a plasma to break down thegas, the substrate 1 being placed on an electrode at a temperature of250° C.

[0103] To grow an N-type a-Si film 13, silane gas at 500 sccm andphosphene gas at 0.1 sccm to 1 sccm are introduced into the plasma CVDapparatus chamber, the pressure within which is 0.5 Torr to 2 Torr, 50 Wto 300 W of high-frequency electrical power (13.56 MHz) being applied toas to generate a plasma to break down the gas, the substrate beingplaced on an electrode at a temperature of 250° C.

[0104] Over the above, a resist pattern 41 is formed, usingphotolithography. This resist pattern 41 is used as an etching mask toetch the ITO film an the a-Si film, thereby obtaining a configurationsuch as shown in FIG. 15.

[0105] Additionally, in the present invention, as shown in FIG. 16(A)and FIG. 16(B), the surface of the solar battery module 3 can be coveredby a protective film 45, or by an antireflection film 46 having areflectance lower than that of the base.

[0106] The resist pattern 41 has as its first purpose that of extractinga lower electrode, its second purpose being that of forming theelectrical generating part and display part. By forming this resistpattern in the shapes such as shown in FIG. 5, FIG. 6, FIG. 7, and FIG.8, it is possible to form a solar battery module 3 having an electricalgenerating part 6.

[0107] When forming the pattern of the ITO which serves as the lowerelectrode film 14, if parts other than the extraction electrode are madethe same resist pattern, the transmissivity at the display part isincreased.

[0108] The etching of the ITO is done as described above, using dryetching, etching of the a-Si film 13 being done continuously in this dryetching apparatus.

[0109] The etching of the a-Si film 13 is done by introducing SF6 at 100sccm to 300 sccm and C12 gas at 0 sccm to 100 sccm into the dry etchingapparatus chamber, the overall pressure therein being 50 mTorr to 200mTorr, and 100 W to 1000 W of high-frequency electrical power (13.56MHz) being applied so as to generate a plasma.

[0110] Additionally, after stripping the resist pattern, the elementsare connected in series using a conductive paste, so that a combinedelectromotive force is generated. Then, a transparent resin or the likeis applied to the upper surface as a protective film, thereby completinga solar battery having a connection structure such as shown in FIG.19(B).

[0111]FIG. 17(A) and FIG. 17(B) show another example of a method formanufacturing a solar battery module 3 of the present invention. Asshown in FIG. 17(A), first a transparent electrode 12, an a-Si film 13and a transparent electrode as a lower electrode are formed on atransparent substrate 1, over which an appropriate resist 48 is formed,this resist being appropriately patterned, the resist pattern 48 beingused as a mask, as shown in FIG. 7(B), to perform simultaneous etchingof the transparent electrode 12, the a-Si film 13, and the transparentelectrode 14, thereby forming the narrow linear elements 35 that make upthe solar battery 6.

[0112]FIG. 18(A) through FIG. 18(F) are drawing showing an example of amethod for forming a connection electrode between adjacent solarbatteries 6 wherein, as shown in FIG. 18(B), an ITO 12 film is grown asa lower electrode on thee top of a glass substrate 1, over which is thenformed a desired resist pattern 40.

[0113] This resist pattern is used as an etching mask to etch the ITO12, the result being as shown in FIG. 18(C).

[0114] When this is done, if the solar battery is to be formed as shownin FIG. 15, the electrical generating area is made by forming a resistpattern such as shown in FIG. 14, and if the shape of FIG. 17(B) is tobe obtained, the electrical generating area is covered entirely byresist, as shown in FIG. 18(B).

[0115] Next, after stripping the resist, the a-Si film 13 and ITO 12 toserve as the upper electrode are continuously grown, as shown in FIG.18(D), over which a desired resist pattern 41 is formed.

[0116] Additionally, using this resist pattern 41 as an etching mask,the ITO upper electrode film 14 and a-Si film 13 are etched.

[0117] In a case in which the ITO film that serves as the lowerelectrode is etched to the same type of shape as indicated in FIG.18(B), after etching, without peeling, a new resist pattern 42 is formedas a cover in only the joining parts shown in FIG. 18(G), and the ITOfilm is further etched in this condition.

[0118] In order to obtain the shape of FIG. 15, this process step is notnecessary.

[0119] After the above, the resist is peeled away, a conductive paste 80is used to join the lower electrode 12 and the upper electrode 14, andthe protective film 81 is applied, thereby resulting in the structure ofFIG. 18(F).

[0120] The dry etching of the ITO in this embodiment of the presentinvention is done, for example, by introducing HBr gas at 100 sccm to200 sccm and argon gas at 0 sccm to 50 sccm into the dry etchingapparatus chamber, the pressure within being 20 mTorr to 50 mTorr, andapplying 1000 W to 2000 W of high-frequency electrical power (13.56 MHz)so as to generate a plasma.

[0121] The basic configuration of a solar battery module as noted abovein the present invention is one in which a solar battery is formed on atransparent substrate surface, the solar battery having narrow linearelements so that a major transparent portion of the transparentsubstrate is not blocked, and the solar battery being formed so as toprotrude from at least one main surface of the transparent substrate.

[0122] Therefore, it is desirable that the solar battery module of thepresent invention be covered with a transparent protective film, andfurther preferable that the side walls of the solar battery beconfigured so as to form a light incidence part.

[0123] Additionally, in the solar battery module of the presentinvention it is preferable that the plurality of narrow linear elementsbe disposed so as to be mutually parallel or adjacent with a prescribedspacing therebetween, and further it is required that the width of thenarrow linear elements and the arrangement spacing between narrow linearelements be established so that the narrow linear elements in the solarbattery be unperceivable by the human eye.

[0124] The narrow linear elements in the solar battery module of thepresent invention can be either straight line or curved, and it isdesirable that the transmissivity of the solar battery be 70% orgreater.

[0125] The width of the narrow linear elements that make up the solarbattery module is 200 μm or smaller, and preferably 20 μm or smaller.

[0126] The spacing between the plurality of narrow linear elementsmaking up the solar battery module of the present invention ispreferably at least 50 μm.

[0127] Additionally, it is preferable that the design be such that theportion of surface area of the transparent substrate used in the solarbattery module of the present invention that is occupied by theplurality of narrow linear elements be 20% or less.

[0128] If a solar battery module 3 configured as noted above isfabricated so that the portion of surface area occupied by elements is20% and the display part surface area is 80%, 80% of the light istransmitted, making it usable as a watch face. When the element size isless than 100 microns, it becomes difficult to recognize with a humaneye, thereby becoming substantially transparent. That is, it is possibleto make the design with freedom, and no restrictions with regard to thewatch face.

[0129] By designing the solar battery, it is possible to achieve a newwatch with an added design on the watch face.

[0130] As described above, with the present invention, in a solarbattery formed by growing an amorphous silicon film onto a substrate, bymaking the minimum width of the amorphous silicon 200 μm, so that it isnot perceivable with the naked eye, it is possible to imparttransparency to the substrate onto which the solar battery is formed,thereby enabling the manufacturing of a solar battery applicable to anyindustrial product in which a design is required.

1. An electronic apparatus in which a major portion of an informationdisplay means is covered by a transparent substrate having a solarbattery, said solar battery being formed on said transparent substrateas a narrow linear element, so as to not block a major transparentportion of the transparent substrate, and formed so that the solarbattery protrudes minimally at one main surface of the transparentsubstrate.
 2. An electronic apparatus in which a major portion of aninformation display means is covered by a transparent substrate having asolar battery, said solar battery being formed on said transparentsubstrate as a narrow linear element, so as to not block a majortransparent portion of the transparent substrate, and formed so that thesolar battery protrudes minimally at one main surface of the transparentsubstrate, said transparent substrate that includes said solar batterybeing disposed on the light incidence side with respect to theinformation display means, and said solar battery formed so as toprotrude from said transparent substrate being formed on a surface ofsaid transparent substrate opposing said information display means. 3.An electronic apparatus in which a major portion of an informationdisplay means is covered by a transparent substrate having a solarbattery, said solar battery being formed on said transparent substrateas a narrow linear element, so as to not block a major transparentportion of the transparent substrate, and formed so that the solarbattery protrudes minimally at one main surface of the transparentsubstrate, said transparent substrate that includes said solar batterybeing disposed on the light incidence side with respect to theinformation display means, and said solar battery formed so as toprotrude from said transparent substrate being formed on a surface ofsaid transparent substrate opposite from the surface opposing saidinformation display means.
 4. An electronic apparatus according to anyone of claim 1 to claim 3, wherein the protruding height of said solarbattery from said transparent substrate is such that the total of theheights (H1+H2) on both sides of the solar battery on both side wallsformed along the longitudinal direction of the solar battery is 1% to30% of the total of the length (H1+H2+L) summing up a length L of aportion of a cross-sectional area protruding from the transparentsubstrate and formed perpendicular to the longitudinal direction of saidsolar battery and which being substantially parallel to said transparentsubstrate, and a total of the two heights (H1+H2) corresponding to theside walls on both sides thereof.
 5. An electronic apparatus accordingto any one of claim 1 to claim 4, wherein said part of said solarbattery protruding from said transparent substrate is covered by atransparent protective film.
 6. An electronic apparatus according to anyone of claim 1 to claim 5, wherein a side wall part of said solarbattery forms a light-incidence part.
 7. An electronic apparatusaccording to any one of claim 1 to claim 6, wherein said side wall partof said solar battery is configured so that part of the light that istransmitted through the transparent substrate or light reflected fromthe transparent substrate is incident thereto.
 8. An electronicapparatus according to any one of claim 1 to claim 7, wherein saidinformation display means is one type selected from a group of, aliquid-crystal display, a plate on a surface of which numerals orgraphics are shown and an indicating board of a watch, or the like. 9.An electronic apparatus according to any one of claim 1 to claim 7,wherein said electronic apparatus is an electronic watch.
 10. Anelectronic apparatus according to any one of claim 1 to claim 9, whereinsaid plurality of narrow linear elements are disposed so as to bemutually parallel or disposed so as to have a prescribed spacingtherebetween.
 11. An electronic apparatus according to any one of claim1 to claim 10, wherein a width of said narrow linear elements and aspacing between said narrow linear elements are established so that saidnarrow linear elements are not perceivable to the human eye.
 12. Anelectronic apparatus according to any one of claim 1 to claim 10,wherein said narrow linear elements are straight lines or curved lines.13. An electronic apparatus according to any one of claim 1 to claim 12,wherein the transmissivity of said solar battery is 70% or greater. 14.An electronic apparatus according to any one of claim 1 to claim 13,wherein the width of said narrow linear elements forming said solarbattery is 200 μm or smaller.
 15. An electronic apparatus according toclaim 14, wherein the width of said narrow liner elements forming saidsolar battery is 20 μm or smaller.
 16. An electronic apparatus accordingto any one of claim 1 to claim 15, wherein the spacing between saidplurality of narrow linear elements forming said solar battery is atleast 50 μm.
 17. An electronic apparatus according to any one of claim 1to claim 16, wherein the portion of surface area of said transparentsubstrate occupied by said solar battery is 20% or less.
 18. Anelectronic apparatus according to any one of claim 1 to claim 17,wherein a group of a plurality of narrow linear elements formed on saidtransparent substrate are connected mutually in parallel.
 19. Anelectronic apparatus according to any one of claim 1 to claim 18,wherein a group of a plurality of narrow linear elements formed on saidtransparent substrate are divided into mutually different subgroups, theplurality of narrow linear elements in each individual subgroup beingconnected mutually in parallel, and the plurality of subgroups beingconnected mutually in series.
 20. An electronic apparatus according toclaim 19, wherein said plurality of narrow linear elements disposedmutually parallel and forming one subgroup is interleaved among saidplurality of narrow linear elements disposed mutually parallel andforming another subgroup.
 21. An electronic apparatus according to anyone of claim 18 to 20, wherein said plurality of narrow linear elementsdisposed mutually parallel and forming one subgroup is disposed so thatthe arrangement direction thereof is different from that of saidplurality of narrow linear elements disposed mutually parallel andforming another subgroup
 22. An electronic apparatus according to anyone of claim 1 to claim 21, wherein said solar battery comprises atransparent electrode layer disposed at a part in contact with thetransparent substrate, an electrical generating layer provided incontact with said transparent electrode layer, and an electrode layermade of a metal layer or a transparent electrode layer provided incontact with said electrical generating layer.
 23. An electronicapparatus according to claim 22, wherein both said electrode layers ofsaid solar battery are transparent electrode layers.
 24. An electronicapparatus according to claim 21 or 22, wherein said electricalgenerating layer is an amorphous silicon film.
 25. An electronicapparatus according to any one of claim 1 to claim 24, wherein a surfaceof said information display means is configured so as to be able toreflect incident light.
 26. A solar battery module in which a solarbattery is formed on a surface of a transparent substrate, said solarbattery having a narrow linear element so as not to block a majortransparent portion of said transparent substrate, and said solarbattery being formed so as to protrude from at least one main surface ofsaid transparent substrate.
 27. A solar battery module according toclaim 26, wherein said solar battery is covered by a protective film.28. A solar battery module according to claim 26 or claim 27, wherein aside wall part of said solar battery is configured as a light-incidencepart.
 29. A solar battery module according to any one of claim 26 toclaim 28, wherein a plurality of narrow linear elements are disposed soas to be mutually parallel or disposed so as to have a prescribedspacing therebetween.
 30. A solar battery module according to any one ofclaim 26 to claim 28, wherein the width of a plurality of said narrowlinear elements and the spacing between each said narrow linear elementsare established so that said narrow linear elements in said solarbattery is not perceivable to the human eye.
 31. A solar battery moduleaccording to any one of claim 26 to claim 30, wherein said narrow linearelements are straight lines or curved lines.
 32. A solar battery moduleaccording to any one of claim 26 to claim 31, wherein the transmissivityof said solar battery is 70% or greater.
 33. A solar battery moduleaccording to any one of claim 26 to claim 32, wherein the width of saidnarrow linear elements forming said solar battery is 200 μm or smaller.34. A solar battery module according to claim 33, wherein the width ofsaid narrow linear elements forming said solar battery is 20 μm orsmaller.
 35. A solar battery module according to any one of claim 36 toclaim 34, wherein the spacing between said plurality of narrow linearelements forming said solar battery is at least 50 μm.
 36. A solarbattery module according to any one of claim 26 to claim 35, wherein theportion of surface area of the transparent substrate occupied by saidsolar battery is 20% or less.
 37. A solar battery module according toany one of claim 26 to claim 36, wherein a group of narrow linearelements formed on said transparent substrate are connected mutually inparallel.
 38. A solar battery module according to any one of claim 26 toclaim 37, wherein said plurality of narrow linear elements formed onsaid transparent substrate is divided into a plurality of subgroups, theplurality of narrow linear elements of each subgroup being connected inmutually parallel, and said subgroups being connected mutually inseries.
 39. A solar battery module according to claim 38, wherein aplurality of narrow linear elements disposed mutually parallel formingone subgroup is interleaved between a plurality of narrow linearelements disposed mutually parallel and forming another subgroup.
 40. Asolar battery module according to claim 38 or claim 39, wherein aplurality of narrow linear elements disposed mutually parallel andforming one subgroup is disposed with an arrangement direction that isdifferent from the arrangement direction of a plurality of narrow linearelements disposed mutually parallel and forming another subgroup.
 41. Awatch with a solar battery, in which a solar battery module is disposedon top of a watch face.
 42. A watch with a solar battery, in which asolar battery is disposed on a protective glass crystal.
 43. A watchwith a solar battery, in which a solar battery module is disposed belowa protective glass crystal.
 44. A watch with a solar battery accordingto any one of claim 41 to claim 43, wherein the solar battery module hasan electrical generating section and a display part.
 45. A watch with asolar battery according to any one of claim 41 to claim 44, wherein asolar battery element is in the shape of a spider's web.
 46. A watchwith a solar battery according to any one of claim 41 to claim 45,wherein a solar battery element is formed by a plurality of parallellines.